Radio tuning system



Aug. 13, 1929.

A. ROTH 1,724,371

RADIO TUNING SYSTEM Filed April 15, 1925 a /2 /4 Q- I g 2 3 g 5 f 2 E 2W E E m s E E L? M w. M Q J F":

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ATTORNEY Patented Aug. 13, 1929.

UNITED STATES 1,124,371 PATENT orrics.

ALBERT ROTH, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY; A CORPORATION OF PENNSYLVANIA.

RADIO TUNING SYSTEM.

Application filed April 15, 1925. Serial No. 23,415.

My invention relates to radio signalling systems and particularly to means for adjusting variable impedances incorporated in radio receiving systems.

An object of my invention is to provide a more convenient means for adjusting the impedance elements of radio circuits.

Another object of my invention is to provide a more convenient adjusting means having an indicating means cooperating therewith.

Another object of my invention is'to provide a tuning means adapted to control the variable impedance elements of two resonant circuits, whereby the two control means are conveniently moved simultaneously at different rates.

Another object of my invention is to provide a convenient tuning means for a supen heterodyne radio. receiving system.

Another object of my invention is to provide a vertical disc tuning means only a portion of which is accessible to the operator.

Another object of my invention is to pro vide a tuning adjustment means having an indicating means cooperating therewith that is adapted to be marked with suitable indexing means according to the choice and location of'the particular operator.

Another object of my invention is to provide a radio tuning means having a dial upon which station logs can be written and which are easily changed at the desire of the operator.

In the construction of radio receiving ap paratus, a wide variety of graduated tuning adjustment means have been used for ,the purpose of adjusting and indicating the 'setting of various types of variable impedances.

None of these devices have proven' wholly satisfactory for the wide variety of requirements encountered.

Most of the variable impedance elements are equipped with a rotatable shaft which is adapted to project through a front panel. Upon this shaft have customarily been mounted such devices as graduated dials, having the graduations' upon a sloping edge at the periphery.

Other indicating means have been used in the form of handles having a. pointer with an index line or a tapered end adapted to travel over a fixed scale. These tuning means all require the use of the thumb and fingers of the operator for the operation of adjusting one and when the circuit requires that several be moved simultaneously both hands of the operator must be employed.

This has been found particularly difficult in .the case of the superheterodyne receiving system, in which there are two resonant circuits which must be tuned simultaneously with a fixed frequency difference between them. In the construction of the usual receiving system of this sort both of the operators hands are required'to adjust the circuits.

The superheterod-yne system uses a loop antenna, and the setting of the dials for a given wave length'does not, therefore, vary when the apparatus is moved from place to place, since the same antenna is used wherever the set may be. For this reason, it is highly desirable that it be possible to mark .upon the dials the setting for various stations within convenient range of the receiving apparatus. With the types of tuning dials at present in use, such marking has been found to be difficult.

My invention provides a convenient tuning system embodying two tuning adjustment means which are conveniently simultaneously movable by the fingers of one hand at different uniform rates of movement. My invention further provides a convenient index means upon which the call letters of the stations may be marked for convenient reference. The indexing means is further adapted to have the marks thereon readily chan ed at the will of the user.

0t er objects and structural details of my invention will be apparent from the following description when read in connection with the accompanying drawing, wherein Figure 1 is a plan view of an embodiment of my invention,

Fig. 2 is an end view in vertical elevation of an embodiment of m invention; and

Fig. 3 is a fragmentary ront view of an embodiment of my invention.

Referring to the drawing, a front panel 1 has secured thereto, a plurality of variable impedance devices which may be variable condensers 2, 3, and 4 having shafts 5, 6 and 7 respectively. To shaft 6 is attached a disk 8, a segment of which projects through an opening 9 in the panel 1. A second disk 11 is attached to the shaft 7 find a. segment of it likewise projects through another portion of panel opening 9 To the disk 8 attached a drum preferably'of aluminum, a portion of the surface and ink or by a lead pencil.

opening ,9.

A second'and similar drum 14 is attached to the. disk 11 and a portion of its surface likewise projects through the pan'elopening 9. A pointer spanning the opening 9 is attached to the front .of the panel 1. This pointer is adapted to cover the space between the drums 12 and 14 and it carries a reference mark 16 adapted to cooperate with index graduations upon the drums 12 and 14.

The. aluminum drums 12 and 14 may be indcxedin any suitable manner as by degree indications, at the adjacent edges thereof during the process of manufacture. The remaining surfaces of these drums are then adapted to be written upon either by pen Thecall letters of stations which the user is accustomed to hear may thus be marked for future reference. 4

In the operation of my device each of the drums 8 and 11 may be conveniently rotated in either direction by contact of a. single finger. The spacing between them is less than the convenient reach of an operators fingers and he is thereby enabled to rotate the disks simultaneously, thus varying the values of the connected adjustable. impedances.

The operator in moving the drums simultaneously is able to move them at variable rates of speed by a'twisting motion of his wrist simultaneously with the up and down movement given his fingers, and he is thereby enabled to move them simultaneously but at the different rate required for the purpose of maintaining the constant frequency differences.

By this means, I am enabled to tune a radio receiving apparatus with much greater ease, simplicity and convenience than has been posslble by previous devices. Also, I

am enabled tojindex upon an easily changed dial the tuning positions for a variety of stations and to change these marks as the choice of stations varies.

While Ihave shown but a simple embodiment of my invention in the accompanying description, it is capable of various modifL .cations therefrom without departing from ments may be controlled by the fingers of a single hand.

2. In combination, a plurality of variable impedance devices each comprising a stationary element and a rotatableelement, a panel having an opening therethrough,

means. for maintaining the axes of rotation to one another that all of said rotatable eleof the rotatable elements in substantial alignment and substantially parallel toa face of said panel, and means for adjusting the position of the rotatable elements, said adjusting means comprising a plurality of relatively large discs positioned adjacent to one another and so disposed with respect to the opening in said panel as to slightly project therethrough, whereby said rotatable elements may be simultaneously adjusted by the fingers of a single hand.

In testimony whereofll have hereunto subscribed my name this fith-dayof April, 1925. 4

ALBERT Born. 

